* {
    padding: 0;
    margin: 0;
}

ul {
    list-style: none;
}

.banner {
    width: 1000px;
    height: 400px;
    margin: 50px auto;
    position: relative;
    overflow: hidden;
    a {
        position: absolute;
        width: 50px;
        height: 100px;
        background: url(../images/left.png) no-repeat;
        background-size: contain;
        top: 150px;
        display: none;
        &:last-child {
            right: 0px;
            background: url(../images/right.png) no-repeat;
            background-size: contain;
        }
    }
    ul {
        position: absolute;
        right: 20px;
        bottom: 20px;
        .active {
            background: red;
        }
        li {
            width: 20px;
            height: 20px;
            border-radius: 50%;
            background: lightblue;
            float: left;
            margin-left: 10px;
            cursor: pointer;
        }
    }
    .inner {
        width: 1000px;
        height: 400px;
        position: absolute;
        left: 0;
        top: 0;

        img {
            width: 1000px;
            height: 400px;

            float: left;
        }
    }
}
